<template>
  <div>
    <h1>App</h1>
    count:{{ count }} <button @click="count++">+</button>
  </div>
</template>

<script setup>
import { ref, watch } from "vue";
const count = ref(1);

watch(count, (newValue, oldValue) => {
  console.log(newValue, oldValue);
});






</script>